Solid oxide fuel cells

Abstract

To provide a solid oxide fuel cell capable of increasing the heating efficiency and raising the temperature of an inner structure to a target temperature (an operation temperature) in a short time and with low energy.SOLUTION: A solid oxide fuel cell 100 comprises: an electrolyte ceramic 3; an electrode part 1 that comprises an anode electrode 4 and a cathode electrode 5 sandwiching the electrolyte ceramic 3 from both sides; a metal frame 2 arranged around the electrode part 1 so as to sandwich the electrode part 1 from both sides, being physically in contact with the anode electrode 4 and the cathode electrode 5, respectively; and a power feeding port 7 electrically connected with the metal frame 2 to feed high-frequency power to the metal frame 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a solid oxide fuel cell. [Background technology]

[0002] A solid oxide fuel cell (SOFC) is a fuel cell in which a cell is constructed by sandwiching an electrolyte ceramic between an anode layer and a cathode layer. SOFCs have a high operating temperature, and the internal structure (cell, etc.) must be heated to nearly 700 degrees to start generating electricity.

[0003] A conventional method for heating SOFCs is to heat the external structure (such as the housing) using a gas burner. However, this method using a gas burner has the problem that the internal structure is indirectly heated using heat applied to the external structure, resulting in low heating efficiency and requiring a long time and a large amount of energy for the internal structure to reach the target temperature (operating temperature). Another problem with the method using a gas burner is that it generates emissions such as NOx (nitrogen oxides).

[0004] Therefore, a method of heating the power generating body (cell) of an SOFC by irradiating it with microwaves has been proposed (see, for example, Patent Document 1). This heating method using microwaves suppresses the generation of emissions such as NOx (nitrogen oxides). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-165516 Summary of the Invention [Problem to be solved by the invention]

[0006] However, conventional heating methods using microwaves do not provide sufficiently high heating efficiency, and there is still the problem that it takes a long time and a large amount of energy for the internal structure to reach the target temperature (operating temperature).

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a solid oxide fuel cell that has high heating efficiency and can raise the temperature of the internal structure to a target temperature (operating temperature) in a short time with little energy. [Means for solving the problem]

[0008] The solid oxide fuel cell of the present invention comprises an electrode section including an electrolyte ceramic and an anode electrode and a cathode electrode sandwiching the electrolyte ceramic from both sides, a metal frame arranged around the electrode section so as to sandwich the electrode section from both sides and being in physical contact with the anode electrode and the cathode electrode, respectively, and a power supply port electrically connected to the metal frame for supplying high-frequency power to the metal frame.

[0009] With this configuration, when power is supplied from the power supply port to the metal frame arranged around the electrode unit, high frequency waves are supplied directly to the electrode unit through the metal frame, and the electrode unit is heated by the supplied high frequency waves. In this case, the internal structure (electrode unit) is directly heated using the high frequency waves applied to the internal structure, so the temperature of the internal structure can be raised to the target temperature (operating temperature) with high heating efficiency and in a short time with little energy.

[0010] Furthermore, the solid oxide fuel cell of the present invention may comprise a plurality of the electrode portions and a plurality of the metal frames, the electrode portions and the metal frames being arranged alternately and in series and electrically connected, the power supply port being electrically connected to the metal frame that is positioned outermost among the plurality of metal frames, and the high-frequency power being supplied from the power supply port to the metal frame that is positioned outermost.

[0011] With this configuration, multiple electrodes arranged in series are electrically connected via the metal frame. In terms of an electrical circuit, these electrodes can be considered as series-connected capacitors. Therefore, by supplying power from the power supply port to the outermost metal frame, high-frequency power can be supplied uniformly to all of the electrodes.

[0012] Furthermore, the solid oxide fuel cell of the present invention may include an impedance matching circuit connected to the power supply port, and the impedance matching circuit may be configured to match the impedance of the electrode portion with the impedance of a high-frequency oscillator that generates the high-frequency wave.

[0013] With this configuration, the impedance of the high-frequency oscillator that generates the high frequency is matched with the impedance of the electrode unit, thereby improving the transmission efficiency of the high frequency supplied to the electrode unit. For example, the impedance of the high-frequency oscillator and the impedance of the electrode unit may be measured in advance (such as before shipping from the factory).

[0014] In the solid oxide fuel cell of the present invention, the impedance matching circuit may be configured to match the impedance of the high-frequency oscillator to the impedance of the electrode section, which varies depending on the temperature of the electrode section.

[0015] With this configuration, even if the impedance of the electrode section changes in response to temperature changes in the electrode section (temperature changes from room temperature to nearly 700°C), the impedance of the high-frequency oscillator can be matched with the impedance of the electrode section. Therefore, it is possible to prevent a decrease in the transmission efficiency of the high-frequency wave supplied to the electrode section due to temperature changes in the electrode section. For example, the change in impedance of the electrode section with respect to temperature may be measured in advance to determine desired impedance matching circuit conditions for each temperature, and the impedance matching circuit may be varied in response to the temperature of the electrode section.

[0016] In the solid oxide fuel cell of the present invention, the high-frequency oscillator that generates the high-frequency wave may include a power control unit that controls the high-frequency power supplied to the power supply port in accordance with the temperature of the electrode unit.

[0017] With this configuration, the high-frequency power supplied to the power supply port is controlled according to the temperature of the electrode unit. When the temperature of the electrode unit increases, less high-frequency power needs to be supplied to the power supply port (compared to when the temperature of the electrode unit is low). Therefore, by reducing the high-frequency power supplied to the power supply port as the temperature of the electrode unit increases, the total amount of high-frequency power supplied can be reduced.

[0018] The solid oxide fuel cell of the present invention may also include a pulse drive control section that pulse-drives the high-frequency oscillator that generates the high-frequency wave on a time axis.

[0019] According to this configuration, the high-frequency oscillator is controlled to be pulse-driven on the time axis (pulse drive control). Even if the high-frequency oscillator is pulse-driven (for example, on-off control), the temperature of the electrode portion can be sufficiently increased by setting the duty ratio of the on-off control so that the temperature increase during the on-time exceeds the temperature decrease during the off-time. When the high-frequency oscillator is on-controlled, high-frequency power is supplied to the power supply port, but when the high-frequency oscillator is off-controlled, high-frequency power is not supplied to the power supply port. Therefore, the total amount of high-frequency power supplied can be reduced. Furthermore, even if the heated cells are unevenly positioned, the cell temperature is dispersed during the off-time, making the cell temperature uniform. Furthermore, by reducing the continuous operation time of the high-frequency oscillator, the life of the high-frequency oscillator can be extended.

[0020] Furthermore, the solid oxide fuel cell of the present invention may be configured to include a switch circuit that switches the destination of the high-frequency power supplied from the high-frequency oscillator to the power supply port to the power supply port of another solid oxide fuel cell, and a switch drive control unit that switches the switch circuit.

[0021] According to this configuration, the switch drive control unit controls the switch circuit to switch the destination of the high-frequency power supplied from the high-frequency oscillator to the power supply port to the power supply port of another solid oxide fuel cell. This makes it possible to continuously supply high-frequency power from one high-frequency oscillator to the power supply ports of multiple solid oxide fuel cells over time. For example, the duty ratio of the switch drive control may be varied according to the temperature difference between the electrodes of each solid oxide fuel cell. It may also be varied according to the ratio of the physical sizes of each solid oxide fuel cell. [Effects of the Invention]

[0022] According to the present invention, the temperature of the internal structure can be raised to a target temperature (operating temperature) with high heating efficiency, in a short time, and with little energy. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is an explanatory diagram showing the configuration of a solid oxide fuel cell according to a first embodiment of the present invention. [Figure 2] 1 is a perspective view of a main part of a solid oxide fuel cell according to a first embodiment of the present invention. [Figure 3] FIG. 4 is an explanatory diagram showing the configuration of a solid oxide fuel cell according to a second embodiment of the present invention. [Figure 4] FIG. 10 is an explanatory diagram showing the configuration of a solid oxide fuel cell according to a third embodiment of the present invention. [Figure 5] FIG. 10 is an explanatory diagram showing the configuration of a solid oxide fuel cell according to a fourth embodiment of the present invention. [Figure 6] FIG. 10 is an explanatory diagram showing the configuration of a solid oxide fuel cell according to a fifth embodiment of the present invention. [Figure 7] FIG. 10 is an explanatory diagram showing the configuration of a solid oxide fuel cell according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A solid oxide fuel cell according to an embodiment of the present invention will now be described with reference to the accompanying drawings. In the present embodiment, a solid oxide fuel cell used in electronic devices, electric vehicles, etc. will be described as an example.

[0025] (First embodiment) The configuration of a solid oxide fuel cell according to a first embodiment of the present invention will be described with reference to the drawings. Figure 1 is an explanatory diagram showing the configuration of the solid oxide fuel cell according to this embodiment, and Figure 2 is a perspective view of the main part of the solid oxide fuel cell according to this embodiment.

[0026] As shown in Figures 1 and 2, a solid oxide fuel cell 100 of this embodiment includes a flat electrode unit 1 and a flat metal frame 2 that is arranged to sandwich the electrode unit 1 from both sides (top and bottom in Figure 1). The metal frame 2 has an opening in the center (see Figure 2). The electrode unit 1 is composed of a flat electrolyte ceramic 3 (dielectric), and an anode electrode 4 and a cathode electrode 5 that sandwich the electrolyte ceramic 3 from both sides (top and bottom in Figure 1). It can be said that the electrode unit 1 and the metal frame 2 constitute a cell unit 6 (cell configuration).

[0027] The metal frame 2 is in physical contact with the anode electrode 4 and the cathode electrode 5. In the example of FIG. 1, the upper metal frame 2 is in physical contact with the anode electrode 4, and the lower metal frame 2 is in physical contact with the cathode electrode 5. A power supply port 7 is electrically connected to the metal frame 2. A high-frequency oscillator 8 is electrically connected to the power supply port 7, and high-frequency (e.g., microwave) power is supplied from the power supply port 7 to the metal frame 2.

[0028] The sizes of the anode electrode 4 and the cathode electrode 5 are set larger than the size of the electrolyte ceramic 3. For example, the sizes of the anode electrode 4 and the cathode electrode 5 are 50.4 mm in length, 23.7 mm in width, and 0.18 mm in thickness, and the size of the electrolyte ceramic 3 is 49.6 mm in length, 19.8 mm in width, and 0.2 mm in thickness. The size of the metal frame 2 is set larger than the sizes of the anode electrode 4 and the cathode electrode 5, and the size of the opening in the metal frame 2 is set smaller than the sizes of the anode electrode 4 and the cathode electrode 5. For example, the size of the metal frame 2 is 65 mm in length, 41 mm in width, and 0.6 mm in thickness, and the size of the opening in the metal frame 2 is 48 mm in length and 18 mm in width.

[0029] The sizes of the anode electrode 4, the electrolyte ceramic 3, and the cathode electrode 5 are not limited to those described above. For example, the anode electrode 4 may be 53.5 mm long, 23.5 mm wide, and 0.3 mm thick, the electrolyte ceramic 3 may be 53.5 mm long, 23.5 mm wide, and 0.03 mm thick, and the cathode electrode 5 may be 50 mm long, 20 mm wide, and 0.2 mm thick.

[0030] The anode electrode 4 is made of, for example, NiO (nickel oxide), and the cathode electrode 5 is made of, for example, LSCF (lanthanum-strontium-cobalt-iron) or LSM (lanthanum-strontium-manganese).The electrolyte ceramic 3 is made of, for example, YSZ (yttria-stabilized zirconia) or GDC (gadolinium-doped ceria), and the metal frame 2 is made of, for example, SUS (stainless steel).

[0031] In the solid oxide fuel cell 100 according to the first embodiment of the present invention, when power is supplied from the power supply port 7 to the metal frame 2 arranged around the electrode unit 1, high frequency waves are supplied directly to the electrode unit 1 through the metal frame 2, and the electrode unit 1 is heated by the supplied high frequency waves. In this case, the internal structure (electrode unit 1) is directly heated using the high frequency waves applied to the internal structure, so that the temperature of the internal structure can be raised to a target temperature (operating temperature) with high heating efficiency, in a short time, and with little energy.

[0032] (Second embodiment) Next, a solid oxide fuel cell according to a second embodiment of the present invention will be described. Here, the differences between the solid oxide fuel cell according to the second embodiment and the first embodiment will be mainly described. Unless otherwise specified, the configuration and operation of this embodiment are the same as those of the first embodiment.

[0033] FIG. 3 is an explanatory diagram showing the configuration of a solid oxide fuel cell according to this embodiment. As shown in FIG. 3, in a solid oxide fuel cell 200 according to this embodiment, a plurality of cell units 6 are arranged in series and electrically connected to one another. A gas separator S is disposed between the cell units 6. The separator S is made of, for example, mica. Even when a separator S is provided between the cell units 6, the metal frames 2 of the cell units 6 are electrically connected to one another via a connection C (see FIG. 3). The material of the connection C may be, for example, the same material (metal) as that of the metal frame 2.

[0034] In the solid oxide fuel cell 200 of this embodiment, a plurality of cell units 6 are stacked (laminated) to form one stack unit 9 (stack configuration). The power supply port 7 is electrically connected to the metal frames 2 of the plurality of cell units 6 that are arranged on the outermost sides (the top and bottom sides in FIG. 3 ), and high-frequency power is supplied from the power supply port 7 to the metal frames 2 arranged on the outermost sides.

[0035] The solid oxide fuel cell 200 according to the second embodiment of the present invention also provides the same effects as those of the first embodiment.

[0036] Furthermore, in this embodiment, multiple electrode units 1 arranged in series are electrically connected via the metal frame 2 and the connection unit C, and these electrode units 1 can be regarded as series-connected capacitors in terms of an electrical circuit. Therefore, by supplying power from the power supply port 7 to the metal frame 2 arranged on the outermost side, high-frequency power can be supplied uniformly to all electrode units 1.

[0037] (Third embodiment) Next, a solid oxide fuel cell according to a third embodiment of the present invention will be described. Here, the differences between the solid oxide fuel cell according to the third embodiment and the second embodiment will be mainly described. Unless otherwise specified, the configuration and operation of this embodiment are the same as those of the second embodiment.

[0038] FIG. 4 is an explanatory diagram showing the configuration of a solid oxide fuel cell according to this embodiment. As shown in FIG. 4, a solid oxide fuel cell 300 according to this embodiment includes an impedance matching circuit 10. The impedance matching circuit 10 is connected to a high-frequency oscillator 8 and a power supply port 7, and has the function of matching the impedance of the high-frequency oscillator 8 with the impedance of the electrode unit 1. In power transmission, the transmission efficiency is highest when the impedance of the output side (high-frequency oscillator 8) matches the impedance of the load side (electrode unit 1). The impedance matching circuit 10 has the function of matching the impedance of the high-frequency oscillator 8 with the impedance of the electrode unit 1.

[0039] Furthermore, this impedance matching circuit 10 may have a function of matching the impedance of the high-frequency oscillator 8 to the impedance of the electrode unit 1, which changes depending on the temperature of the electrode unit 1. The impedance of the electrode unit 1 changes depending on the temperature of the electrode unit 1. This is because the dielectric constant of the electrolyte ceramic 3 has the property of changing depending on temperature. By varying the impedance matching circuit 10 depending on the temperature of the electrode unit 1, high transmission efficiency can be maintained even when the temperature of the electrode unit 1 changes. Note that making the impedance matching circuit 10 variable depending on temperature can be easily achieved, for example, by configuring the impedance matching circuit 10 with a capacitor and using a varicap for the capacitor to voltage-control the capacitor capacitance depending on temperature, or by using a capacitor that itself has temperature characteristics.

[0040] The solid oxide fuel cell 300 according to the third embodiment of the present invention also provides the same effects as those of the first embodiment.

[0041] Furthermore, in this embodiment, the impedance of high-frequency oscillator 8 that generates high-frequency waves is matched with the impedance of electrode unit 1, thereby improving the transmission efficiency of high-frequency waves supplied to electrode unit 1. For example, the impedance of high-frequency oscillator 8 and the impedance of electrode unit 1 may be measured in advance (such as at the time of shipping from a factory).

[0042] Furthermore, in this embodiment, even if the impedance of the electrode unit 1 changes in response to a change in temperature of the electrode unit 1 (temperature changes from room temperature to nearly 700°C), the impedance of the high-frequency oscillator 8 can be matched with the impedance of the electrode unit 1. Therefore, it is possible to prevent a decrease in the transmission efficiency of the high frequency supplied to the electrode unit 1 due to a change in temperature of the electrode unit 1. For example, the change in impedance of the electrode unit 1 with respect to temperature may be measured in advance to determine the desired conditions of the impedance matching circuit 10 for each temperature, and the impedance matching circuit 10 may be varied in response to the temperature of the electrode unit 1.

[0043] (Fourth embodiment) Next, a solid oxide fuel cell according to a fourth embodiment of the present invention will be described. Here, the differences between the solid oxide fuel cell according to the fourth embodiment and the second embodiment will be mainly described. Unless otherwise specified, the configuration and operation of this embodiment are the same as those of the second embodiment.

[0044] FIG. 5 is an explanatory diagram showing the configuration of a solid oxide fuel cell according to this embodiment. As shown in FIG. 5, a solid oxide fuel cell 400 according to this embodiment includes a temperature sensor 11 that measures the temperature of the electrode unit 1 and a power control unit 12 that controls the high-frequency power supplied to the power supply port 7 in accordance with the temperature of the electrode unit 1. For example, even when heating the electrode unit 1 to 700°C, the high-frequency power required differs depending on whether the electrode unit 1 is heated from room temperature (25°C) or from 400°C. Therefore, the temperature of the electrode unit 1 is measured by the temperature sensor 11, and the power output from the high-frequency oscillator 8 is controlled by the power control unit 12 in accordance with the measured temperature. For example, when the temperature of the electrode unit 1 is low, the output power from the high-frequency oscillator 8 is increased, and when the temperature of the electrode unit 1 is high, the output power from the high-frequency oscillator 8 is decreased.

[0045] The solid oxide fuel cell 400 according to the fourth embodiment of the present invention also provides the same effects as those of the first embodiment.

[0046] Furthermore, in this embodiment, the high-frequency power supplied to the power supply port 7 is controlled in accordance with the temperature of the electrode unit 1. When the temperature of the electrode unit 1 increases, less high-frequency power needs to be supplied to the power supply port 7 (compared to when the temperature of the electrode unit 1 is low). Therefore, by reducing the high-frequency power supplied to the power supply port 7 in accordance with the increase in the temperature of the electrode unit 1, the total amount of high-frequency power supplied can be reduced. This allows the solid oxide fuel cell 400 to be started up efficiently and quickly with the minimum necessary power.

[0047] (Fifth embodiment) Next, a solid oxide fuel cell according to a fifth embodiment of the present invention will be described. Here, the differences between the solid oxide fuel cell according to the fifth embodiment and the second embodiment will be mainly described. Unless otherwise specified, the configuration and operation of this embodiment are the same as those of the second embodiment.

[0048] Fig. 6 is an explanatory diagram showing the configuration of a solid oxide fuel cell according to this embodiment. As shown in Fig. 6, a solid oxide fuel cell 500 according to this embodiment includes a pulse drive control unit 13 that pulse-drives a high-frequency oscillator 8 on a time axis. The pulse drive control unit 13 controls the on / off of the high-frequency oscillator 8 at regular time intervals (e.g., 60-second intervals) when heating the solid oxide fuel cell 500 to a predetermined target temperature (e.g., 700°C).

[0049] The solid oxide fuel cell 500 according to the fifth embodiment of the present invention also provides the same effects as those of the first embodiment.

[0050] Furthermore, in this embodiment, the high-frequency oscillator 8 is controlled to be pulse-driven on the time axis (pulse drive control). Even if the high-frequency oscillator 8 is pulse-driven (for example, on-off control), the temperature of the electrode unit 1 can be sufficiently increased by setting the duty ratio of the on-off control so that the temperature increase during the on-time exceeds the temperature decrease during the off-time. When the high-frequency oscillator 8 is on-controlled, high-frequency power is supplied to the power supply port 7, but when the high-frequency oscillator 8 is off-controlled, high-frequency power is not supplied to the power supply port 7. Therefore, the total amount of high-frequency power supplied can be reduced. Furthermore, even if the heated cells are unevenly positioned, the cell temperature is dispersed during the off-time, making the cell temperature uniform. Furthermore, by reducing the continuous operation time of the high-frequency oscillator 8, the life of the high-frequency oscillator 8 can be extended.

[0051] (Sixth embodiment) Next, a solid oxide fuel cell according to a sixth embodiment of the present invention will be described. Here, the differences between the solid oxide fuel cell according to the sixth embodiment and the second embodiment will be mainly described. Unless otherwise specified, the configuration and operation of this embodiment are the same as those of the second embodiment.

[0052] Fig. 7 is an explanatory diagram showing the configuration of a solid oxide fuel cell according to this embodiment. As shown in Fig. 7, a solid oxide fuel cell 600 according to this embodiment includes a plurality of stack units 9 (two in the example of Fig. 7) as destinations of high frequency power. The solid oxide fuel cell 600 according to this embodiment also includes a switch circuit 14 for switching the destination of the high frequency power, and a switch drive control unit 15 for switching the switch circuit 14.

[0053] The switch drive control unit 15 controls the switch circuit 14 to switch the supply destination of the high frequency power at regular time intervals (e.g., every 60 seconds). For example, in the example of Fig. 7, the switch circuit 14 controls the high frequency power to be supplied from the high frequency oscillator 8 to the power supply port 7 of one stack unit 9 (the upper stack unit 9 in Fig. 7) for a certain period of time (e.g., 60 seconds), and then controls the switch circuit 14 to supply the high frequency power from the high frequency oscillator 8 to the power supply port 7 of the other stack unit 9 (the lower stack unit 9 in Fig. 7) for the next certain period of time (e.g., 60 seconds).

[0054] The solid oxide fuel cell 600 according to the sixth embodiment of the present invention also provides the same effects as those of the first embodiment.

[0055] Furthermore, in this embodiment, the switch drive control unit 15 controls the switch circuit 14 to switch the destination of the high frequency power supplied from the high frequency oscillator 8 to the power supply port 7 to the power supply port 7 of another solid oxide fuel cell (stack unit 9). This makes it possible to supply high frequency power from one high frequency oscillator 8 to the power supply ports 7 of multiple solid oxide fuel cells (stack units 9) continuously over time. For example, the duty ratio of the switch drive control may be varied according to the temperature difference between the electrode units 1 of the respective solid oxide fuel cells (stack units 9). It may also be varied according to the ratio of the physical sizes of the respective solid oxide fuel cells (stack units 9).

[0056] Although the embodiments of the present invention have been described above by way of example, the scope of the present invention is not limited to these, and can be modified and changed according to the purpose within the scope of the claims. [Industrial Applicability]

[0057] As described above, the solid oxide fuel cell according to the present invention has the advantage of being highly efficient in heating and capable of raising the temperature of the internal structure to a target temperature (operating temperature) in a short time with little energy, and is therefore useful for use in electronic devices, electric vehicles, etc. [Explanation of symbols]

[0058] 1 Electrode part 2 Metal Frame 3. Electrolyte ceramic 4 anode electrode 5. Cathode electrode 6 cell unit (cell configuration) 7 Power Port 8 High Frequency Oscillator 9 Stack Units (Stack Configuration) 10 Impedance matching circuit 11 Temperature Sensor 12 Power control section 13 Pulse drive control section 14 Switch Circuit 15 Switch drive control section 100, 200, 300, 400, 500, 600 Solid Oxide Fuel Cell

Claims

1. an electrode portion including an electrolyte ceramic and an anode electrode and a cathode electrode sandwiching the electrolyte ceramic from both sides; a metal frame disposed around the electrode portion so as to sandwich the electrode portion from both sides and physically contacting the anode electrode and the cathode electrode; a power supply port electrically connected to the metal frame for supplying microwave power to the metal frame; A solid oxide fuel cell comprising:

2. a cell unit is configured by the electrode portion and the metal frame, and a plurality of the cell units are arranged in series and electrically connected to each other; the power supply port is electrically connected to the metal frame arranged on the outermost side among the metal frames of the plurality of cell units; 2. The solid oxide fuel cell according to claim 1, wherein the microwave is supplied from the power supply port to the outermost metal frame.

3. an impedance matching circuit connected to the power supply port; 3. The solid oxide fuel cell according to claim 1, wherein the impedance matching circuit is configured to match the impedance of the electrode portion with the impedance of a high-frequency oscillator that generates the microwaves.

4. 4. The solid oxide fuel cell according to claim 3, wherein the impedance matching circuit is configured to match the impedance of the high-frequency oscillator to the impedance of the electrode portion, which changes depending on the temperature of the electrode portion.

5. 5. The solid oxide fuel cell according to claim 1, wherein the high-frequency oscillator that generates the microwaves includes a power control unit that controls the power of the microwaves supplied to the power supply port in accordance with the temperature of the electrode portion.

6. 6. The solid oxide fuel cell according to claim 1, further comprising a pulse drive control section that pulse-drives the high-frequency oscillator that generates the microwaves on a time axis.

7. 7. The solid oxide fuel cell according to claim 6, further comprising: a switch circuit that switches the supply destination of microwave power supplied from the high-frequency oscillator to the power supply port of another solid oxide fuel cell; and a switch drive control unit that switches the switch circuit.

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